The Oligopeptide Synthesis Core Facility is intended to be shared resource administered and guided by the Faculty to enable investigators in the University of Chicago Cancer Research Center to obtain custom-made oligopeptides in the shortest time and at the lowest cost with maximum versatility. The oligopeptides will be used to investigate the functional domain of known proteins, to study the interaction of proteins with receptors, membranes, or DNA, to study the specificity of proteolytic enzymes, to verify the existence of genes deduced from nucleotide sequence, and to separate related gene products based on heterogeneity of small domains of the proteins. The need to create such a facility within the University is based on (1) the usefulness of the facility for training in research techniques, (2) the frequent need to synthesize large arrays of related peptides differing in only one amino acid, and (3) the need to control directly the quality of product.